felbamate (Felbatol)
Jump to navigation
Jump to search
Introduction
Tradename: Felbatol.
Indications
- monotherapy & adjunctive therapy in patients > 14 years of age with partial & secondary generalized seizures
- adjunctive therapy in patients > 2 years of age with partial & generalized Lennox-Gastaut syndrome
- reserve drug for patients with severe symptoms NOT responsive to other, less toxic agents
- intractable seizures[4]
Contraindications
- avoid in patients with liver failure[7]
Dosage
- Start 400 mg PO TID, max 3.6 g/day
- Pediatrics: Start 15 mg/kg/day, max 45 mg/kg/day
- do NOT discontinue abruptly
Tabs: 400 & 600 mg.
Suspension: 600 mg/5 mL.
Dosage adjustment in renal failure
Monitor
- complete blood count (CBC) baseline, weekly during therapy & for 4 weeks after discontinuation[6]
- liver function tests (LFTs)baseline & weekly
Adverse effects
- common (> 10%)
- less common (1-10%)
- drowsiness, insomnia, blurred or double vision, clumbsiness, weight gain, depression, behavioral changes, clouded sensorium, lethargy, muscle twitches, slurred speech, uncontrollable eye movements, acne, skin rash
- uncommon (< 1%)
- other (serious)
- aplastic anemia (marked increased incidence)
- hepatotoxicity
Drug interactions
- felbamate increases levels of phenytoin, valproic acid
- felbamate decreases carbamazepine level, but increases epoxide
- phenytoin & carbamazepine decrease felbamate levels
- drug interaction(s) anticonvulsants with anti-bacterial agents
- drug interaction(s) anticonvulsants with statins
Mechanism of action
- potentiates GABA receptor-linked Cl- channels
- inhibits spontaneous discharges from voltage-dependent Na+ channels
- inhibits NMDA receptors
- inhibits AMPA receptors[5]
More general terms
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 702
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 4.0 4.1 Department of Veterans Affairs, VA National Formulary
restricted to neurology - ↑ 5.0 5.1 UpToDate 13.3 http://www.utdol.com
- ↑ 6.0 6.1 Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=260704&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 7.0 7.1 7.2 Medical Knowledge Self Assessment Program (MKSAP) 17, American College of Physicians, Philadelphia 2015